66 Cab Upper Floor - Common rust area- Any mods or prepping to prevent?

[msg]

You see it all the time, the floors are rusted out where all that road crud spins off the front wheels and cakes on the cabs upper floor area. Im repairing mine now but in doing so I was wondering what flaw there is that might be corrected here. Was it just a not so great paint type they used? Bad seam sealer? Instead of having to be super diligent and wash off the muck often, is there a good approach to keep this from happening all over again?





Borrowing a pic from Racecougar on this one, hope he doesnt mind

[Cape Codder]

Trucks were made to work and wear out. They didn't spend a lot trying to make them last as that gets expensive and they price themselves out of the market. After repairing I would prime with an epoxy primer then paint and coat the outside with a rubberized undercoat. Seam seal your seams after priming before paint.

[VictoriaHardware]

They rusted from both the inside and the outside. Poor design on the inside that trapped water and held it in the outboard corners. Poor metal prep on both sides that really didn't do much for rust prevention. The prep and paint you're using today is much better than what was used in the 60's. You also are not likely to abuse the truck, so it is likely to last must longer than the original.

[jdl71]

Are you fabricating your own patch? I've not seen this section available anywhere.

[mark 66]

I had to replace pretty much all the metal from the fire wall down to floor.after all metal was replaced I sparyed the bottom with 3m shutz under coat